Lately I have been having problems with Hatching. For example, on a large site plan I am working on I have hatched all the buildings. This site plan has a lot of other things on it, such as contours, water courses, trees, etc. I have saved and closed the plan. Then upon reopening it, everything is great, EXCEPT the hatching which has disappeared! This has happened to me more than once, in more than one drawing. The weird thing is that it is relatively new. (I do remember other plans that were fine, with the hatching entact each time I opened it!) What is going on?